1. Field of the Invention
The present invention relates to a seat slide apparatus comprising a long lower rail mounted on a floor surface for mounting a seat in a longitudinal direction, and an upper rail slidably supported so as to be guided on the long lower rail in a longitudinal direction and mounted and fixed to a seat main body side.
2. Description of the Related Art
Generally, a seat for a vehicle is provided with a seat main body constituted by a seat cushion, a seat back rotatably stood at the rear thereof, and the like. The structure is made such that the seat can be slidably adjusted in a longitudinal direction of a vehicle body by supporting the seat cushion of the like constituting the seat main body on the vehicle floor surface via a longitudinal slide mechanism, thereby capable of variously changing a layout of the seat within a passenger""s room.
Further, as the longitudinal slide mechanism for the seat, there is employed a seat slide apparatus comprising a long lower rail formed in a longitudinal direction in a vehicle body floor surface side, mounted on the vehicle body floor surface side and provided so as to have substantially the same height as a surface of a floor carpet, and an upper rail mounted and fixed to a seat main body side.
As shown in FIGS. 1 and 2, in the proposed seat slide apparatus 1, each of a pair of right and left lower rails 2 is provided with a main body portion 2a formed by a metal plate member and having a substantially upward U shape, and a pair of right and left engaging portions 3 inward bent from front end sides of both side portions 2b in the main body portion 2a and having downward suspended front end sides, whereby an opening portion 3a is formed in an end portion of the engaging portion 3.
A pair of upper rails 5 of the seat slide apparatus 1 are formed in a substantially inverted-T shape so as to be assembled in the lower rails 2, and engaged portions are formed in both side portions bent upward from the front end sides of the horizontal portions of the upper rails 5. The engaged portions are engageably combined with the engaging portions 3 in a side of the lower rails 2.
Further, a vertical portion formed in an inverted-T shape in the upper rail 5 protrudes upward from the opening portion 3a of the lower rail 2, and an anchor member, a shaft of a seat lifter, a base of a reclining mechanism and the like are mounted thereto. A roller 7 is inserted to a portion between the lower arm 2 and the upper rail 5 in a state of being supported by a roller shaft 7a. 
When the roller 7 is interposed between the lower rail 2 and the upper rail 5 so as to be slidably supported, it is possible to prevent at some level problems that a slide resistance is rapidly increased or reduced, a malfunction is generated due to a change of the sliding resistance caused by a noise or a load at a time of starting, and the like, in comparison with a conventional structure in which the slide mechanism is obtained by a simple sliding motion between metal surfaces.
However, in the case that the proposed seat slide apparatus 1 mentioned above is long formed, it is complicated to work respective parts, there is a problem that a play is generated due to an error of size in the respective portions or the like, and there has a disadvantage that a dispersion of size in the respective portions of the vehicle and the seat can not be absorbed. Accordingly, there has a risk that a slide operating force is increased and a smooth slide motion of the upper rail 5 can not be obtained when an inclination is generated in the roller 7 between the lower rail 2 and the upper rail 5 as shown in FIG. 2.
An object of the present invention is to provide a seat slide apparatus satisfied with below effects:
(1) The seat slide apparatus can improve the strength of a long lower rail.
(2) The seat slide apparatus can prevent a deformation of an upper rail.
(3) The seat slide apparatus can form an opening portion of the long lower rail so as to prevent dusts on a floor surface from dropping down within the lower rail from the opening portion of the lower rail.
(4) The seat slide apparatus can have a simple structure and require no additional new parts or installing operation.
(5) The seat slide apparatus can have an inexpensive cost.
(6) The seat slide apparatus can rapidly perform a mounting operation.
(7) The seat slide apparatus can obtain a smooth and stable sliding motion.
(8) The seat slide apparatus can reduce a frictional resistance, so as to improve the performance of an operation thereof.
The first aspect of the invention provides A seat slide apparatus comprising: a long lower rail mounted on a floor surface for mounting a seat in a longitudinal direction; and an upper rail supported in such a manner as to be slidably guided in a longitudinal direction on the long lower rail and mounted and fixed to a seat main body side, wherein the long lower rail is provided with a main body portion having a substantially upward U shape, and a pair of right and left upper side portions inward extended from front end sides of both side portions of the main body so as to form an opening portion, and roller receiving step are formed in both sides of a bottom portion of the main body portion, wherein the upper rail has a main body portion having a substantially downward U shape in such a manner as to be assembled in the long lower rail, and a vertical wall protruding upward from a center of an upper wall of the main body portion and protruding upward from an opening portion of the upper side portion in the long lower rail, wherein a roller is inserted to a portion between the step of the bottom portion of the main body portion in the long lower rail and the upper wall of the main body portion in the upper rail, circular arc surfaces are formed in both side portions of the roller, and the both side portions of the roller are mounted to the step of the bottom portion of the main body portion in the long lower rail, and wherein a circular arc surfaces are formed of the roller receiving step in the long lower rail, and the circular arc surfaces of the roller and the circular arc surfaces of the roller receiving step in the long lower rail are in surface contact with each other.
The second aspect of the invention provides a seat slide apparatus according to the first aspect of the invention, wherein a first slider receiving portion is formed in a lower surface side of the upper side portion in the long lower rail, and a second slider portion is formed in an upper wall of the main body portion in the upper rail, and wherein a slider is inserted to a portion between the first slider receiving portion and the second slider receiving portion.
The third aspect of the invention provides a seat slide apparatus according to the first aspect of the invention, wherein the both side portions of the roller are formed so as to have a larger diameter than that of a center portion.
The fourth aspect of the invention provides a seat slide apparatus according to the first aspect of the invention, wherein a clearance is provided between an end portion of the roller and side walls of the main body portion in the upper rail, and a washer is provided in the clearance in such a manner as to be inserted to the end portion of the roller.
The fifth aspect of the invention provides a seat slide apparatus according to the first aspect of the invention, wherein first hooks are formed in front end portions in a side of an opening portion of the main body portion in the long lower rail, and second hooks are formed in both side portions of the main body portion, respectively.
The sixth aspect of the invention provides a seat slide apparatus according to the fifth aspect of the invention, wherein first engaging portions engaged with the first hooks are respectively formed in upper walls of the main body portion in the upper rail, and second engaging portions engaged with the second hooks are respectively formed in front end sides of both side portions of the main body portion in the upper rail.